The invention relates generally to a projection screen arrangement.
One form of projection screen arrangement comprises a tubular housing in which there is mounted a spring-loaded roller, for winding in and winding out the projection screen. A rotary handle or knob which can be actuated from the outside of the housing is provided at one end thereof, and is nonrotatably connected to the roller for tensioning the projection screen when in the extended position. The end of thwe projection screen which is remote from the roller usually has a terminal bar member. As the force of the spring for winding in the projection screen so as to retract it automatically into the housing is generally not sufficient to hold the projection screen absolutely flat and taut when in the extended condition, the rotary knob is used for subsequently tensioning the projection screen in the extended position, by manual rotation of the knob.
It has been found that projection screen arrangements with automatic winding-in means of the above-indicated general kind suffer from the disadvantage that, in their wound-in or rolled-up condition, the location at which the projection screen member is secured to the winding-in roller, usually by the end portion of the screen member being engaged into the roller, causes pressure to be applied to the layers of the screen which are disposed thereabove around the winding-in roller, due to the force applied by the spring means loading the roller into the retracted condition of the screen member, and such pressure results in transverse strips or stripe markings being formed on the screen when in the extended condition. It will be appreciated that such markings interfere and detrimentally affect the quality of reproduction of an image on the screen